Tough Times Ahead for 100-Yen Stores

TOKYO—Japanese investors and exporters may be cheering the dollar's return to the ¥100 mark, but for the thousands of "100 Yen" discount stores around the country, it signals tough times ahead.

The 100-yen shops have become representative of a deflationary Japan, thriving by astonishing customers with the purchasing power of the ¥100 coin. They offer everything from cellphone chargers to fake eyelashes for the same low...